The present invention relates to an apparatus for damping the noise generated by a rail wheel such as a railroad wheel.
Vehicles traveling on rails cause noise in the track. Such noises are generated at the points where the wheels contact the rails. Such noises are mainly the result of a superposition of rolling vibrations, sliding contact noises and rotational vibrations. The noise generated in this manner is radiated on the one hand as sound traveling through the air from the rail and track system. On the other hand, vibrational noise components propagating in solids such as the wheels and rails are transmitted directly through the rails as well as through the wheels from the point where the noise is generated. Due to structural considerations, for example, of a railroad system, it is not possible to completely eliminate the generation of noise, especially in track sections forming a curve.
A flanged rail wheel is known which is noise dampened by means of a layer of synthetic material applied to the wheel disc. The layer of synthetic material reaches from the hub area over the wheel disc proper into the inner edge of the wheel rim. A wheel cover of sheet metal covering substantially the same area as the layer of synthetic material is secured on top of the layer of synthetic material. The wheel cover is held in position by the bonding or adhesive action of the synthetic material.
One disadvantage of this type of noise damping device is seen in that, once applied, the device cannot be removed from the wheel disc without being destroyed in the process. However, it is necessary to inspect the wheel disc from time to time for detecting any starting fatigue cracks and the like. For this purpose this type of prior art noise damping device must be removed and replaced by a new one after the inspection. On the other hand, the inspection could be performed only on one side of the rail wheel. However, that is not satisfactory for safety reasons. Furthermore, it has been found that the efficiency of damping masses which are directly applied to the vibrating body depends directly on the quantity of the applied damping material. Thus, substantial quantities of damping synthetic material must be applied to the wheel in accordance with the prior art in order to achieve the desired damping effect. Such substantial quantities, of course, increase the weight of the wheels, which is also undesirable.